** The depth of field ( aka depth of focus) of a lens with a small aperture
is very wide - even a moderate telephoto lens can, when set to F16 or
higher, be in good focus from a couple of metres to infinity.

Interestingly - the depth of field of a lens depends only on the size of
the field of view and the F number. When the subject is very small ( ie
like a postage stamp) then the depth diminishes to a millimetre or so.